1.5 Comments

indent formats both C and C++ comments. C comments are begun with
‘/*’, terminated with ‘*/’ and may contain newline characters.
C++ comments begin with the delimiter ‘//’ and end at the newline.

indent handles comments differently depending upon their context.
indent attempts to distinguish between comments which follow
statements, comments which follow declarations, comments following
preprocessor directives, and comments which are not preceded by code of
any sort, i.e., they begin the text of the line (although not
necessarily in column 1).

indent further distinguishes between comments found outside of
procedures and aggregates, and those found within them. In particular,
comments beginning a line found within a procedure will be indented to
the column at which code is currently indented. The exception to this
is a comment beginning in the leftmost column; such a comment is output
at that column.

indent attempts to leave boxed comments unmodified. The
general idea of such a comment is that it is enclosed in a rectangle or
“box” of stars or dashes to visually set it apart. More precisely,
boxed comments are defined as those in which the initial ‘/*’ is
followed immediately by the character ‘*’, ‘=’, ‘_’, or
‘-’, or those in which the beginning comment delimiter (‘/*’)
is on a line by itself, and the following line begins with a ‘*’ in
the same column as the star of the opening delimiter.

Examples of boxed comments are:

/**********************
* Comment in a box!! *
**********************/
/*
* A different kind of scent,
* for a different kind of comment.
*/

indent attempts to leave boxed comments exactly as they are found
in the source file. Thus the indentation of the comment is unchanged,
and its length is not checked in any way. The only alteration made is
that an embedded tab character may be converted into the appropriate
number of spaces.

If the ‘-bbb’ option is specified, all such boxed comments will be
preceded by a blank line, unless such a comment is preceded by code.

Comments which are not boxed comments may be formatted, which means that
the line is broken to fit within a right margin and left-filled with
whitespace. Single newlines are equivalent to a space, but blank lines
(two or more newlines in a row) are taken to mean a paragraph break.
Formatting of comments which begin after the first column is enabled
with the ‘-fca’ option. To format those beginning in column one,
specify ‘-fc1’. Such formatting is disabled by default.

The right margin for formatting defaults to 78, but may be changed with
the ‘-lc’ option. If the margin specified does not allow the
comment to be printed, the margin will be automatically extended for the
duration of that comment. The margin is not respected if the comment is
not being formatted.

If the comment begins a line (i.e., there is no program text to its
left), it will be indented to the column it was found in unless the
comment is within a block of code. In that case, such a comment will be
aligned with the indented code of that block (unless the comment began
in the first column). This alignment may be affected by the ‘-d’
option, which specifies an amount by which such comments are moved to
the left, or unindented. For example, ‘-d2’ places comments
two spaces to the left of code. By default, comments are aligned with
code, unless they begin in the first column, in which case they are left
there by default — to get them aligned with the code, specify ‘-fc1’.

Comments to the right of code will appear by default in column 33.
This may be changed with one of three options. ‘-c’ will specify
the column for comments following code, ‘-cd’ specifies the
column for comments following declarations, and ‘-cp’ specifies
the column for comments following preprocessor directives #else
and #endif. ‘-dj’ together with ‘-cd0’ can be used
to suppress alignment of comments to the right of declarations, causing the
comment to follow one tabstop from the end of the declaration. Normally ‘-cd0’
causes ‘-c’ to become effective.

If the code to the left of the comment exceeds the beginning column,
the comment column will be extended to the next tabstop column past
the end of the code, or in the case of preprocessor directives, to one
space past the end of the directive. This extension lasts only for
the output of that particular comment.

The ‘-cdb’ option places the comment delimiters on blank lines.
Thus, a single line comment like /* Loving hug */ can be
transformed into:

/*
Loving hug
*/

Stars can be placed at the beginning of multi-line comments with the
‘-sc’ option. Thus, the single-line comment above can be
transformed (with ‘-cdb -sc’) into: